Power semiconductor modules have electrical connecting contacts for the electrical connection of module-external components, the contacts being accessible from the exterior of the module and being electrically conductively connected to one or more power semiconductor chips or other components arranged in the interior of the module. In this case, the electrical connection is realized by low-resistance electrical conductors, which are designated as connecting lugs hereinafter.
In this case, there is the requirement that such connecting lugs can be connected to the housing in the simplest possible manner, and that a connection arises which is sufficiently stable so that a force acting on that part of the connecting lug which is situated outside the housing is not transmitted to other, in particular module-internal, components in an impermissible manner.
Besides stable fixing, it is additionally necessary to ensure that the connecting lugs assume a defined position in the housing if the connecting lugs are connected module-internally to electronic components of the module by bonding wires in order that a high, reproducible bonding quality can be ensured during the production of a bonding connection between a bonding wire and a connecting lug. These requirements are particularly stringent in the case of thick copper-based bonding wires having diameters of 300 μm or more, since copper-based bonding wires are significantly harder than the aluminum-based bonding wires usually used, such that the bonding process requires significantly higher forces with which the bonding wire is pressed against the connecting lug during the bonding operation.
A further aspect concerns, for example, the mounting of a module cover on a housing frame pre-equipped with the connecting lugs, and the mounting of the finished module on a printed circuit board. These steps require a high degree of dimensional and positional stability and also a high positional accuracy of the connecting contacts formed on the connecting lugs. If the contacts are embodied as plugs, for example, it is possible, in the case of imprecise positioning and orientation, that instances of tilting occur, or that the plugs cannot be threaded through corresponding holes in the printed circuit board. In order to meet these requirements, a high mechanical outlay is currently expended in order to wedge the plugs during mounting in the frame. This has the effect that the position and location of the plugs in the frame can vary. Therefore, it is entirely customary to realign the plugs in the housing frame.